Ask HN: Why the need for newer versions of software?

I feel like when an application software product gets released, there is never an end to the changes to it. Year after year, there are new versions being released. I wonder what actually goes into these new versions.

Some things I get: - For hardware development tools, newer versions will support newer hardware models. - Web browsers need to keep up with the evolution of the web. - Operating systems need to support different form factors and architectures.

But many things I don't get: - Word processors - Spreadsheets - Photo editors

What more functionality do these need? Maybe for a fraction of users, some new features are useful. But when most users use only the established features, why is there such a pressing need to release new software year after year?